JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<table>
  <tr>
    <th>Valor1</th>
    <th>Valor2</th>

  </tr>
  <tr>
    <td><input class="texto" type="text"></td>
    <td><input class="texto" type="text"></td>
  </tr>
  <tr>
    <td><input class="texto" type="text"></td>
    <td><input class="texto" type="text"></td>
  </tr>
</table>

JavaScript

$(function(){  
	$('.texto').on('change', function(){
  
    var col1val1 = $('.texto').eq(0).val();
    var col1val2 = $('.texto').eq(2).val();
    
    var col2val1 = $('.texto').eq(1).val();
    var col2val2 = $('.texto').eq(3).val();
    
    if(col1val1 == col2val1 && col1val1 != ''){
    	alert('Valor igual ao da outra coluna!');
    }
    
    if(col1val2 == col2val2 && col1val2 != ''){
    	alert('Valor igual ao da outra coluna!');
    }
  	
  });
})